C H A P T E R 9 - Multihead Administration

C H A P T E R 9

Multihead Administration

The multihead feature on Sun Ray trademark DTUs enables users to control separate applications on multiple screens, or heads, using a single keyboard and pointer device attached to the primary DTU. Users can also display and control a single application, such as a spreadsheet, on multiple screens. System administrators create multihead groups that may be accessed by users. A multihead group, consisting of between two and 16 DTUs controlled by one keyboard and mouse, may be composed of any mix of Sun Ray DTUs, such as Sun Ray 1, Sun Ray 100, Sun Ray 150, and Sun Ray 170, for instance. Each DTU presents an X screen of the multihead X display.

Note - For the multihead feature to function properly:
1. You must be in administered mode; therefore, you must run utconfig before you run utmhconfig and utmhadm.2. You must enable the multihead policy using either utpolicy or the Admin GUI.
3. Always run utmhconfig from a Sun Ray DTU.

Note - Regional hotdesking is not enabled for multihead groups.

Multihead Groups

A multihead group is comprised of a set of associated Sun Ray DTUs controlled by a primary DTU to which a keyboard and pointer device, such as a mouse, are connected. This group, which can contain a maximum of 16 DTUs, is connected to a single session.

The primary DTU hosts the input devices, such as a keyboard and a pointer device, and the USB devices associated with the session. The remaining DTUs, called the secondaries, provide the additional displays. All peripherals are attached to the primary DTU, and the group is controlled from the primary DTU.

Multihead groups can be created easily by using a smart card to identify the terminals with the utmhconfig GUI utility.

Tip - For best results, run utmhconfig only from a DTU.

However, if you disconnect the secondary DTUs without deleting the multihead group to which they belong, the screens are not displayed on the single primary DTU. The primary DTU is still part of the multihead group, and the mouse seems to get lost when it goes to the disconnected secondary DTU. To recover from this situation, you can either reconnect the missing DTU or delete the multihead group using the utmhconfig or utmhadm command, or you can delete the multihead group, replace the missing DTU, and create a new multihead group that incorporates the replacement DTU.

Multihead Screen Configuration

A multihead group can have its screens arranged in various configurations. For example, a user can arrange a multihead group of four screens as two rows of two screens (2x2) or as a single row of four screens (4x1). By default, when a user logs into a multihead group, the session uses the number of screens available; the layout, or geometry. of these displays is generated automatically. You can use the -R option to utxconfig to manipulate the automatic geometry, as in the following examples:

To override the automatic geometry, where geometry is expressed as columns x rows. type:

% utxconfig -R geometry

To restore the automatic geometry on the next login:

% utxconfig -R auto

When the mouse pointer is moved past the edge between two screens, it moves from one screen to the next. The geometry of the multihead group determines which screen is displayed at that point.

Screen dimensions for the multihead group are automatically set, by default, to the largest supported by the primary DTU. The primary DTU is the one that controls the other DTUs in the group and to which all peripherals are attached.

To override the automatic sizing of screen dimensions, use the -r option to utxconfig:

To override automatic sizing, where dimensions are expressed as width x height (for example, 1280 x 1024):

% utxconfig -r dimensions

To restore automatic sizing behavior on the next login:

% utxconfig -r auto

Note - If explicit screen dimensions are chosen, the user may experience panning or black-band effects.

To explicitly choose not to use multiple displays for a session, type:

% utxconfig -m off

Note - If the resolutions of the monitors differ, you may have problems with unwanted on-screen movement called panning, or large black bands around the visible screen area.

Multihead Screen Display

When the multihead feature is used, a small window indicating the current session on each screen is displayed with the current screen highlighted for easy identification. This window is automatically displayed for users during session creation. For example, the display in XINERAMA indicates that the user is on the second screen of a three-screen display.

FIGURE 9-1 The Multihead Screen Display

This is simply a depiction of window trim showing representations of three small screens. Two are shaded, one is not; this suggests multihead configuration.

Multihead Administration Tool

The administration tool for the multihead feature displays the current multihead groups and enables you to create new groups.

To Turn On Multihead Policy From the Command Line

On the command-line interface, type:

# /opt/SUNWut/sbin/utpolicy -a -m -g your_policy_flags

# /opt/SUNWut/sbin/utrestart

This enables the multihead policy for the failover group and restarts Sun Ray Server Software with the new policy on the local server without disrupting existing sessions.

Tip - Issue the utrestart command on every server in the failover group.

To Turn On Multihead Policy Using the Administration Tool

1. Bring up the Administration Tool by typing the following URL into your browser's location field:

http://hostname:1660

2. Select Admin from the navigation menu on the left side of the tool.

3. Select Policy.

4. Next to Multihead feature enabled, click the Yes radio button.

5. Click the Apply button.

6. Under Admin in the lefthand menu, select Reset Services.

7. Click the Restart button.

This sets the multihead policy for all servers and restarts Sun Ray Server Software on all servers.

To Create a New Multihead Group

1. On the command-line interface, type:

# /opt/SUNWut/sbin/utmhconfig

2. On the initial screen, click Create New Group.

FIGURE 9-2 Multihead Group List With Group Detail

As in other cases, use the utadm and utmh commands instead of the Admin GUI to administer multihead configurations.

The Create New Multiheaded Group pop-up dialog box is displayed. The number of rows and the number of columns you enter are displayed as the group geometry when the group has been created.

FIGURE 9-3 Create New Multiheaded Group Pop-up Dialog Box

As in other cases, use the utadm and utmh commands instead of the Admin GUI to administer multihead configurations.

3. Enter the information for the group.

Enter a name for the group and the number of rows and columns.

4. Click the Next button.

A third screen is displayed.

FIGURE 9-4 Setup Display for the New Multihead Group

As in other cases, use the utadm and utmh commands instead of the Admin GUI to administer multihead configurations.

5. Select the DTUs within the multihead group and insert a smart card in each Sun Ray DTU in turn to establish the order of the group.

The Finish button, which was previously grayed out, is now active.

FIGURE 9-5 Completed Multihead Group List With Active Finish Button

As in other cases, use the utadm and utmh commands instead of the Admin GUI to administer multihead configurations.

6. Click the Finish button.

7. Exit the session or disconnect by removing your card.

XINERAMA

The XINERAMA extension to X11creates one single large screen displayed across several monitors. With XINERAMA, only one toolbar is displayed, and a window can be moved smoothly from one part of the screen to the next.

Tip - Because XINERAMA consumes a lot of CPU, memory and network bandwidth, please set the shmsys:shminfo_shmmax parameter in the /etc/system file to at least LARGEST_NUMBER_OF_HEADS * width * height * 4 for reasonable performance.

Users enable or disable XINERAMA as part of their X preferences. The utxconfig command handles this on an individual token basis. The user must log off for this to take effect.

The XINERAMA feature is enabled using the following command:

% /opt/SUNWut/bin/utxconfig -x on

The XINERAMA feature is disabled using the following command:

% /opt/SUNWut/bin/utxconfig -x off

To enable as default for a single system or failover group, as superuser, type the following command:

% utxconfig -a -x on

Session Groups

If you hot desk from a multihead group to a DTU that is not part of a multihead group--that is, a DTU with a single head--all the screens created in the original multihead group can be viewed on the single screen or head by panning to each screen in turn. This is called screen flipping.

Authentication Manager

The TerminalGroup policy module extends the Authentication Manager to support multihead groups. When a DTU connects to the Authentication Manager or a new smart card is inserted, the TerminalGroup module queries its database to determine whether the DTU is part of a multihead group and, if so, whether the DTU is a primary or secondary DTU of that group. If it is not identified as part of a multihead group, the DTU is treated normally.

FIGURE 9-6 Authentication Manager Flowchart for the Primary DTU

This flow chart asks the following questions: [ D ]

If the DTU is determined to be part of a multihead group and it is the multihead group's primary DTU, a normal session placement occurs. If a session does not exist on the current server, but there is a preexisting session for the DTU or smart card on another server in the failover group, the primary DTU will be redirected to that server. If there is no session on any server, the request for a session is directed to the least-loaded server and a session is created there.

If a DTU is determined to be part of a multihead group and it is a multihead group secondary DTU, the TerminalGroup module determines if the multihead- group primary DTU is locally attached to a session. If it is, it tells the Session Manager to allow the secondary DTU to also attach to that session. If the primary DTU is not attached locally, the TerminalGroup module determines if the primary DTU is attached to another server in the failover group (if any), and if it is, it redirects the secondary DTU to that server.

FIGURE 9-7 Authentication Manager Flowchart for the Secondary DTU

This flow chart asks the following questions: [ D ]

If the primary DTU is determined to not be attached to any server in the failover group at that moment, a "waiting for primary" icon is displayed on the DTU, and further activity is blocked on that DTU until the primary is discovered. The secondary DTU is redirected to the server to which the primary is attached.